机床加工外文文献翻译
机床加工外文文献翻译
(含：英文原文及中文译文)
文献出处：Shunmugam M. Basic Machining Operations and Cutting Technology[J]. Journal of the Institution of Engineers, 2014, 1(2):22-32. 英文原文
Basic Machining Operations and Cutting Technology
Shunmugam M
Basic Machining Operations
Machine was developed from the early Egyptian pedal car and John Wilkinson's trampoline. They provide rigid support for workpieces and tools and can precisely control their relative position and relative speed. Basically, metal cutting refers to a sharpened pry tool that removes a very narrow metal from the surface of a tough workpiece. Chips are discarded products. Compared with other workpieces, the chips are shorter, but there is a certain increase in the thickness of the uncut parts. The geometry of the workpiece surface depends on the shape of the tool and the path of the tool during machining operations.
Most machining processes produce parts of different geometries. If a rough workpiece rotates on the central axis and the tool cuts into the workpiece surface parallel to the center of rotation, a rotating surface is created. This operation is called turning. If a hollow tube is machined on the inner surface in the same way, this operation is called boring. When
the diameter is evenly changed, a conical outer surface is produced, which is called taper turning. If the tool contact point moves in a way that changes the radius, then a workpiece with a contour like a ball is produced; or if the workpiece is short enough and the support is very rigid, then the forming tool normally feeds one outside the axis of rotation. Surfaces can be produced, and short tapered or cylindrical surfaces can also be formed.
Flat surfaces are often required and they can be produced by radial turning of tool contact points with respect to the axis of rotation. It is easier to fix the tool and place the workpiece under the tool for larger workpieces while planing. The tool can feed reciprocally. The forming surface can be produced by a forming tool.
Multi-blade cutters can also be used. Using a double-edged groove drilling depth is 5-10 times the hole diameter. Regardless of whether the drill rotates or the workpiece rotates, the relative motion between the cutting edge and the workpiece is an important factor. During milling, a rotating tool with many cutting edges comes into contact with the workpiece and the workpiece slowly moves relative to the tool. Flat or shaped surfaces may occur depending on the tool geometry and feed method. A horizontal or vertical axis rotation can be generated and can be fed in any of three coordinate directions.
Basic machine
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The Aggregate Machine-tool The Aggregate Machine-tool is based on the workpiece needs, based on a large number of common components, combined with a semi-automatic or automatic machine with a small number of dedicated special components and process according to the workpiece shape and design of special parts and fixtures, composed. Combination machine is generally a combination of the base, slide, fixture, power boxes, multi-axle, tools, etc. From. Combination machine has the following advantages: (1) is mainly used for prism parts and other miscellaneous pieces of perforated surface processing. (2) high productivity. Because the process of concentration, can be multi-faceted, multi-site, multi-axis, multi-tool simultaneous machining. (3) precision and stability. Because the process is fixed, the choice of a mature generic parts, precision fixtures and automatic working cycle to ensure consistent processing accuracy. (4) the development cycle is short, easy to design, manufacture and maintenance, and low cost. Because GM, serialization, high degree of standardization, common parts can be pre-manufactured or mass organizations outsourcing. (5) a high degree of automation, low labor intensity. (6) flexible configuration. Because the structure is a cross-piece, combination. In accordance with the workpiece or process requirements, with plenty of common parts and a few special components consisting of various types of flexible combination of machine tools and automatic lines; tools to facilitate modification: the product or process changes, the general also common components can be reused. Combination of box-type drilling generally used for processing or special shape parts. During machining, the workpiece is generally not rotate, the rotational motion of the tool relative to the workpiece and tool feed movement to achieve drilling, reaming, countersinking, reaming, boring and other processing. Some combination of turning head clamp the workpiece using the machine to make the rotation, the tool for the feed motion, but also on some of the rotating parts (such as the flywheel, the automobile axle shaft, etc.) of cylindrical and face processing. Generally use a combination of multi-axis machine tools, multi-tool, multi-process, multi-faceted or multi-station machining methods simultaneously, productivity increased many times more than generic tools. Since the common components have been standardized and serialized, so can be flexibly configured according to need, you can shorten the design and manufacturing cycle. Multi-axle combination is the core components of general machine tools. It is the choice of generic parts, is designed according to special requirements, in combination machine design process, is one component of a larger workload. It is based on the number and location of the machining process diagram and schematic design combination machine workpiece determined by the hole, cutting the amount of power transmission components and the design of each spindle spindle type movement. Multi-axle power from a common power box, together with the power box installed on the feed slide, to be completed by drilling, reaming and other machining processes. The parts to be processed according to the size of multi-axle box combination machine tool design, based on an original drawing multi-axle diagram, determine the range of design data,
文献综述_人工智能
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Lathes Lathes are machine tools designed primarily to do turning, facing and boring, Very little turning is done on other types of machine tools, and none can do it with equal facility. Because lathes also can do drilling and reaming, their versatility permits several operations to be done with a single setup of the work piece. Consequently, more lathes of various types are used in manufacturing than any other machine tool. The essential components of a lathe are the bed, headstock assembly, tailstock assembly, and the leads crew and feed rod. The bed is the backbone of a lathe. It usually is made of well normalized or aged gray or nodular cast iron and provides s heavy, rigid frame on which all the other basic components are mounted. Two sets of parallel, longitudinal ways, inner and outer, are contained on the bed, usually on the upper side. Some makers use an inverted V-shape for all four ways, whereas others utilize one inverted V and one flat way in one or both sets, They are precision-machined to assure accuracy of alignment. On most modern lathes the way are surface-hardened to resist wear and abrasion, but precaution should be taken in operating a lathe to assure that the ways are not damaged. Any inaccuracy in them usually means that the accuracy of the entire lathe is destroyed. The headstock is mounted in a foxed position on the inner ways, usually at the left end of the bed. It provides a powered means of rotating the word at various speeds . Essentially, it consists of a hollow spindle, mounted in accurate bearings, and a set of transmission gears-similar to a truck transmission—through which the spindle can be rotated at a number of speeds. Most lathes provide from 8 to 18 speeds, usually in a geometric ratio, and on modern lathes all the speeds can be obtained merely by moving from two to four levers. An increasing trend is to provide a continuously variable speed range through electrical or mechanical drives. Because the accuracy of a lathe is greatly dependent on the spindle, it is of heavy construction and mounted in heavy bearings, usually preloaded tapered roller or ball types. The spindle has a hole extending through its length, through which long bar stock can be fed. The size of maximum size of bar stock that can be machined when the material must be fed through spindle. The tailsticd assembly consists, essentially, of three parts. A lower casting fits on the inner ways of the bed and can slide longitudinally thereon, with a means for clamping the entire assembly in any desired location, An upper casting fits on the lower one and can be moved transversely upon it, on some type of keyed ways, to permit aligning the assembly is the tailstock quill. This is a hollow steel cylinder, usually about 51 to 76mm(2to 3 inches) in diameter, that can be moved several inches longitudinally in and out of the upper casting by means of a hand wheel and screw. The size of a lathe is designated by two dimensions. The first is known as the swing. This is the maximum diameter of work that can be rotated on a lathe. It is approximately twice the distance between the line connecting the lathe centers and the nearest point on the ways, The second size dimension is the maximum distance between centers. The swing thus indicates the maximum work piece diameter that can be turned in the lathe, while the distance between centers indicates the maximum length of work piece that can be mounted between centers. Engine lathes are the type most frequently used in manufacturing. They are heavy-duty machine tools with all the components described previously and have power drive for all tool movements except on the compound rest. They commonly range in size from 305 to 610 mm(12 to 24 inches)swing and from 610 to 1219 mm(24 to 48 inches) center distances, but swings up to 1270 mm(50 inches) and center distances up
财务风险中英文对照外文翻译文献
中英文资料外文翻译 财务风险重要性分析 译文： 摘要：本文探讨了美国大型非金融企业从1964年至2008年股票价格风险的决定小性因素。我们通过相关结构以及简化模型，研究诸如债务总额，债务期限，现金持有量，及股利政策等公司财务特征，我们发现，股票价格风险主要通过经营和资产特点，如企业年龄，规模，有形资产，经营性现金流及其波动的水平来体现。与此相反，隐含的财务风险普遍偏低，且比产权比率稳定。在过去30年，我们对财务风险采取的措施有所减少，反而对股票波动（如独特性风险）采取的措施逐渐增加。因此，股票价格风险的记载趋势比公司的资产风险趋势更具代表性。综合二者，结果表明，典型的美国公司谨慎管理的财政政策大大降低了财务风险。因此，现在看来微不足道的剩余财务风险相对底层的非金融公司为一典型的经济风险。 关键词：资本结构；财务风险；风险管理；企业融资 1 绪论 2008年的金融危机对金融杠杆的作用产生重大影响。毫无疑问，向金融机构的巨额举债和内部融资均有风险。事实上，有证据表明，全球主要银行精心策划的杠杆（如通过抵押贷款和担保债务）和所谓的“影子银行系统”可能是最近的经济和金融混乱的根本原因。财务杠杆在非金融企业的作用不太明显。迄今为止，尽管资本市场已困在危机中，美国非金融部门的问题相比金融业的困境来说显得微不足道。例如，非金融企业破产机遇仅限于自20世纪30年代大萧条以来的最大经济衰退。事实上，非金融公司申请破产的事件大都发生在美国各行业（如汽车制造业，报纸，房地产）所面临的基本经济压力即金融危机之前。这令人惊讶的事实引出了一个问题“非金融公司的财务风险是如何重要？”。这个问题的核心是关于公司的总风险以及公司风险组成部分的各决定因素的不确定性。 最近在资产定价和企业融资再度引发的两个学术研究中分析了股票价格风险利
组合机床外文文献
Int J Adv Manuf Technol (2006) 29: 178–183 DOI 10.1007/s00170-004-2493-9
ORIGINAL ARTICLE
Ferda C. C ? etinkaya
Unit sized transfer batch scheduling in an automated two-machine ?ow-line cell with one transport agent
Received: 26 July 2004 / Accepted: 22 November 2004 / Published online: 16 November 2005 ? Springer-Verlag London Limited 2005 Abstract The process of splitting a job lot comprised of several identical units into transfer batches (some portion of the lot), and permitting the transfer of processed transfer batches to downstream machines, allows the operations of a job lot to be overlapped. The essence of this idea is to increase the movement of work in the manufacturing environment. In this paper, the scheduling of multiple job lots with unit sized transfer batches is studied for a two-machine ?ow-line cell in which a single transport agent picks a completed unit from the ?rst machine, delivers it to the second machine, and returns to the ?rst machine. A completed unit on the ?rst machine blocks the machine if the transport agent is in transit. We examine this problem for both unit dependent and independent setups on each machine, and propose an optimal solution procedure similar to Johnson’s rule for solving the basic two-machine ?owshop scheduling problem. Keywords Automated guided vehicle · Lot streaming · Scheduling · Sequencing · Transfer batches entire lot to ?nish its processing on the current machine, while downstream machines may be idle. It should be obvious that processing the entire lot as a single object can lead to large workin-process inventories between the machines, and to an increase in the maximum completion time (makespan), which is the total elapsed time to complete the processing of all job lots. However, the splitting of an entire lot into transfer batches to be moved to downstream machines permits the overlapping of different operations on the same product while work proceeds, to complete the lot on the upstream machine. There are many ways to split a lot: transfer batches may be equal or unequal, with the number of splits ranging from one to the number of units in the job lot. For instance, consider a job lot consisting of 100 identical items to be processed in a three-stage manufacturing environment in which the ?ow of its operations is unidirectional from stage 1 through stage 3. Assume that the unit processing time at stages 1, 2, and 3 are 1, 3, 2 min, respectively. If we do not allow transfer batches, the throughput time is (100)(1+3+2) = 600 min (see Fig. 1a). However, if we create two equal sized transfer batches through all stages, the throughput time decreases to 450 min, a reduction of 25% (see Fig. 1b). It is clear that the throughput time decreases as the number of transfer batches increases. Flowshop problems have been studied extensively and reported in the literature without explicitly considering transfer batches. Johnson [1], in his pioneering work, proposed a polynomial time algorithm for determining the optimal makespan when several jobs are processed on a two-machine (two-stage) ?owshop with unlimited buffer. With three or more machines, the problem has been proven to be NP-hard (Garey et al. [2]). Besides the extension of this problem to the m -stage ?owshop problem, optimal solutions to some variations of the basic two-stage problem have been suggested. Mitten [3] considered arbitrary time lags, and optimal scheduling with setup times separated from processing was developed by Yoshida and Hitomi [4]. Separation of the setup, processing and removal times for each job on each machine was considered by Sule and Huang [5]. On the other hand, ?owshop scheduling problems with transfer batches have been examined by various researchers. Vickson
1 Introduction
Most classical shop scheduling models disregard the fact that products are often produced in lots, each lot (process batch) consisting of identical parts (items) to be produced. The size of a job lot (i.e., the number of items it consists of) typically ranges from a few items to several hundred. In any case, job lots are assumed to be indivisible single entities, although an entire job lot consists of many identical items. That is, partial transfer of completed items in a lot between machines on the processing routing of the job lot is impossible. But it is quite unreasonable to wait for the
F.C. ?etinkaya (u) Department of Industrial Engineering, Eastern Mediterranean University, Gazimagusa-T.R.N.C., Mersin Turkey E-mail: ferda.cetinkaya@https://www.360docs.net/doc/455942957.html,.tr Tel.: +90-392-6301052 Fax: +90-392-3654029